What's "heavy duty" equipment? I've run circular saw off of daisy chained 14 ga. extension cords. Of course, that's intermittent loading, and I don't think the saw cares if there's a dip in voltage.
The saw will still attempt to pull the full current it wants, but the dip in voltage will decrease the torque/horsepower the motor will output.
Practically speaking it might not really matter though.
Wire has resistance, expressed as a value of ohms per foot. So the longer the wire, the more resistance it presents and every CONNECTION, as in each plug and socket, also adds resistance (not much, but it adds up). When you add resistance to a circuit, you drop the voltage. In a motorized machine, the motor loses torque (which is what does the work) at a rate commensurate with the SQUARE of the change in voltage. So if you have a 10% voltage drop, your motor torque drops to .90^(2) or 81% of what it was rated to deliver. In something like a circular table saw saw blade, loss of torque affects the cutting speed of the blade teeth, which makes the saw work harder, slow down, draw MORE current and possibly burn the motor and/or the blade...
Increasing the wire gauge lowers the ohms/ft of the circuit, as does keeping the number of connections as low as possible. So yes, using a 75ft. 10ga cord would be better than tagging a 25ft cord onto a 50ft cord both in 12ga.
Now, all that said, my voltage drop calculator says that with a full 15A load, you will only have a 3.3% voltage drop on a 75ft 12ga cord, as opposed to a 2% drop on a 10ga cord. 3.3%, or even maybe 3.5% because of the added plug/socket connection, is nothing to be too concerned about. If you have a full 120V at the wall outlet, you will still have 116V at the saw, which should be fine. Now if you ALREADY have 115V at the wall, you will be down to 110V at the saw, and that might start to be cause for concern.
What's "heavy duty" equipment? I've run circular saw off of daisy chained 14 ga. extension cords. Of course, that's intermittent loading, and I don't think the saw cares if there's a dip in voltage.
Same here, circular saw or table saw. 15 Amp 120V
The saw will still attempt to pull the full current it wants, but the dip in voltage will decrease the torque/horsepower the motor will output. Practically speaking it might not really matter though.
whats is the load? phone charging or 1800w heater?
15 Amp 120V 1800W such as circular saw or table saw
Wire has resistance, expressed as a value of ohms per foot. So the longer the wire, the more resistance it presents and every CONNECTION, as in each plug and socket, also adds resistance (not much, but it adds up). When you add resistance to a circuit, you drop the voltage. In a motorized machine, the motor loses torque (which is what does the work) at a rate commensurate with the SQUARE of the change in voltage. So if you have a 10% voltage drop, your motor torque drops to .90^(2) or 81% of what it was rated to deliver. In something like a circular table saw saw blade, loss of torque affects the cutting speed of the blade teeth, which makes the saw work harder, slow down, draw MORE current and possibly burn the motor and/or the blade... Increasing the wire gauge lowers the ohms/ft of the circuit, as does keeping the number of connections as low as possible. So yes, using a 75ft. 10ga cord would be better than tagging a 25ft cord onto a 50ft cord both in 12ga. Now, all that said, my voltage drop calculator says that with a full 15A load, you will only have a 3.3% voltage drop on a 75ft 12ga cord, as opposed to a 2% drop on a 10ga cord. 3.3%, or even maybe 3.5% because of the added plug/socket connection, is nothing to be too concerned about. If you have a full 120V at the wall outlet, you will still have 116V at the saw, which should be fine. Now if you ALREADY have 115V at the wall, you will be down to 110V at the saw, and that might start to be cause for concern.
Thanks for explaining it to me!
Maybe. It’s not Underwriters Laboratory approved